KR20200019132A - Intra filtering applied with transform processing in video coding - Google Patents

Abstract

A method of decoding video data comprises position receiving for receiving a block of video data, determining an intra prediction mode for the block of video data, and decoding the block of video data based at least on the determined intra prediction mode. Determining whether to use predictive combination (PDPC) mode. The method also includes receiving a syntax element associated with a primary transform or a secondary transform used for a block of video data, determining the use of one or more video coding tools based on the value of the syntax element. Coding tools include determining the use of the one or more video coding tools, which are video coding techniques other than a primary or secondary transform, and applying one or more coding tools to a block of video data based on the determined use. You may.

Description

Intra filtering applied with transform processing in video coding

This application claims the benefit of US Provisional Application No. 62 / 520,426, filed June 15, 2017, the entire contents of which are incorporated herein by reference.

Technical field

The present disclosure relates to video encoding and video decoding.

Digital video capabilities include digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, Wide range of devices, including digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite cordless phones, so-called "smart phones", video teleconferencing devices, video streaming devices, and the like. Can be incorporated into the Digital video devices are MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4, Part 10, Advanced Video Coding (AVC), High Efficiency Video Coding Implement video coding techniques, such as those defined by Efficiency Video Coding (HEVC or H.265) standard, and extensions of these standards. Video devices may transmit, receive, encode, decode, and / or store digital video information more efficiently by implementing such video coding techniques.

Video coding techniques include spatial (intra picture) prediction and / or temporal (inter picture) prediction to reduce or eliminate redundancy inherent in video sequences. For block based video coding, a video slice (eg, a video frame or part of a video frame) may be partitioned into video blocks, which video blocks may also be treeblocks, coding units (CUs), and / or the like. Or coding nodes. Pictures may be referred to as frames, and reference pictures may be referred to as reference frames.

Spatial or temporal prediction results in a predictive block for the block to be coded. Residual data represents pixel differences between the original block to be coded and the predictive block. For further compression, the residual data may be transformed from the pixel domain to the transform domain, resulting in residual transform coefficients that may later be quantized. Entropy coding may be applied to achieve even more compression.

In general, this disclosure describes techniques related to determining the use of one or more video coding tools. In some examples, the video encoder or decoder may determine the use of the video coding tool based on the intra prediction mode used for the block of video data. In other examples, the video encoder or decoder may determine the use of the video coding tool based on the transform used for the block of video data. Video coding tools include techniques for filtering position-dependent prediction combination (PDPC) mode or intra prediction reference samples (eg, mode dependent intra smoothing (MDIS)). You may. In this way, the video encoder may be configured to signal a syntax element indicating a particular transform and the video decoder may be configured to determine both the transform and the use of a video coding tool from the syntax element for that transform. This may reduce overhead signaling and increase compression efficiency.

In one example, a method of decoding video data includes receiving a block of video data, determining an intra prediction mode for a block of video data, and at least based on the determined intra prediction mode. Determining whether to use the PDPC mode for decoding.

In another example, an apparatus configured to decode video data includes a memory configured to store a block of video data, and one or more processors in communication with the memory, wherein the one or more processors receive a block of video data, Determine an intra prediction mode for a block of and determine whether to use the PDPC mode to decode a block of video data based at least on the determined intra prediction mode.

In another example, an apparatus configured to decode video data includes means for receiving a block of video data, means for determining an intra prediction mode for a block of video data, and at least based on the determined intra prediction mode. Means for determining whether to use the PDPC mode to decode the block.

In another example, the present disclosure describes a non-transitory computer readable storage medium storing instructions, which instructions, when executed, cause one or more processors of a device configured to decode video data to receive a block of video data. Determine an intra prediction mode for a block of video data, and determine whether to use a PDPC mode to decode a block of video data based at least on the determined intra prediction mode.

In another example, a method of encoding video data includes receiving a block of video data, determining an intra prediction mode for encoding a block of video data, and at least based on the determined intra prediction mode. Determining whether to use the PDPC mode to encode the.

In another example, an apparatus configured to encode video data includes a memory configured to store a block of video data, and one or more processors in communication with the memory, wherein the one or more processors receive a block of video data, and Determine an intra prediction mode for encoding a block of, and determine whether to use the PDPC mode to encode a block of video data based at least on the determined intra prediction mode.

Details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description, drawings, and claims.

1 is a block diagram illustrating an example video encoding and decoding system configured to implement the techniques of this disclosure.
2A is a conceptual diagram illustrating an example of block partitioning using a quadtree plus binary tree (QTBT) structure.
FIG. 2B is a conceptual diagram illustrating an example tree structure corresponding to block partitioning using the QTBT structure of FIG. 2A.
3 is an example of 35 intra prediction modes defined in HEVC.
4A illustrates prediction of a 4x4 block using an unfiltered reference in accordance with the techniques of this disclosure.
4B illustrates prediction of a 4x4 block using a filtered reference in accordance with the techniques of this disclosure.
5 illustrates an example of intra reference filtering.
6 is a block diagram illustrating an example of a video encoder configured to implement the techniques of this disclosure.
7 is a block diagram illustrating an example of a video decoder configured to implement the techniques of this disclosure.
8 is a flowchart illustrating an encoding method of an example of the present disclosure.
9 is a flowchart illustrating a decoding method of an example of the present disclosure.

This disclosure describes techniques for coding a block of video data using intra prediction. In some examples, this disclosure describes techniques for prediction directions, intra filtering, transform processing, and determination of video coding tools (eg, specific video coding techniques for video encoding and decoding).

1 is a block diagram illustrating an example video encoding and decoding system 10 that may be configured to perform the techniques of this disclosure for intra prediction filtering and transform processing. As shown in FIG. 1, system 10 includes a source device 12 that provides encoded video data to be decoded later by destination device 14. In particular, source device 12 provides video data to destination device 14 via computer readable medium 16. Source device 12 and destination device 14 may be desktop computers, notebook (eg, laptop) computers, tablet computers, set-top boxes, telephone handsets, such as so-called “smart” phones (or more general). And mobile stations), tablet computers, televisions, cameras, display devices, digital media players, video gaming consoles, video streaming devices, and the like. The mobile station may be any device capable of communicating over a wireless network. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices (eg, mobile stations). Source device 12 is an example video encoding device (ie, a device for encoding video data). Destination device 14 is an example video decoding device (ie, a device for decoding video data).

In the example of FIG. 1, source device 12 includes a video source 18, storage media 20 configured to store video data, video encoder 22, and output interface 24. Destination device 14 includes an input interface 26, storage media 28 configured to store encoded video data, video decoder 30, and display device 32. In other examples, source device 12 and destination device 14 include other components or arrangements. For example, source device 12 may receive video data from an external video source, such as an external camera. Similarly, destination device 14 may interface with an external display device rather than include an integrated display device 32.

The illustrated system 10 of FIG. 1 is just one example. Techniques for processing and / or coding (eg, encoding and / or decoding) video data may be performed by any digital video encoding and / or decoding device. The techniques of this disclosure are generally performed by a video encoding device and / or a video decoding device, but the techniques may also be performed by a video encoder / decoder, commonly referred to as "CODEC". Source device 12 and destination device 14 are merely examples of such coding devices in which source device 12 generates coded video data for transmission to destination device 14. In some examples, source device 12 and destination device 14 may operate in a substantially symmetrical manner such that each of source device 12 and destination device 14 include video encoding and decoding components. For this reason, system 10 may support one-way or two-way video transmission between source device 12 and destination device 14, for example, for video streaming, video playback, video broadcasting, or video telephony. .

Video source 18 of source device 12 is a video capture device, such as a video camera, a video archive containing previously captured video, and / or a video feed for receiving video data from a video content provider. It may also include a video feed interface. As a further alternative, video source 18 may generate computer graphics based data as a source video, or a combination of live video, archived video, and computer generated video. Source device 12 may include one or more data storage media (eg, storage media 20) configured to store video data. The techniques described in this disclosure may be applicable to video coding in general, and may be applied to wireless and / or wired applications. In each case, the captured, pre-captured, or computer-generated video may be encoded by video encoder 22. Output interface 24 may output encoded video information (eg, a bitstream of encoded video data) to computer readable medium 16.

Destination device 14 may receive encoded video data to be decoded via computer readable medium 16. Computer-readable medium 16 may include any type of medium or device capable of moving the encoded video data from source device 12 to destination device 14. In some examples, computer readable medium 16 includes a communication medium that enables source device 12 to transmit encoded video data directly to destination device 14 in real time. The encoded video data may be modulated according to a communication standard, such as a wireless communication protocol, and transmitted to the destination device 14. The communication medium may comprise any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network, such as a local area network, a wide area network, or a global network such as the Internet. The communication medium may include routers, switches, base stations, or any other equipment that may be useful for facilitating communication from source device 12 to destination device 14. Destination device 14 may include one or more data storage media configured to store encoded video data and decoded video data.

In some examples, encoded data may be output from output interface 24 to a storage device. Similarly, encoded data may be accessed from a storage device by an input interface. The storage device may be variously distributed, such as a hard drive, Blu-ray discs, DVDs, CD-ROMs, flash memory, volatile or nonvolatile memory, or any other suitable digital storage medium for storing encoded video data. And may include any of the data storage media that have been accessed or locally accessed. In a further example, the storage device may correspond to a file server or other intermediate storage device that may store the encoded video generated by source device 12. Destination device 14 may access stored video data from the storage device via streaming or download. The file server may be any type of server capable of storing encoded video data and transmitting that encoded video data to the destination device 14. Example file servers include a web server (eg, for a website), an FTP server, network attached storage (NAS) devices, or a local disk drive. Destination device 14 may access the encoded video data via any standard data connection, including an internet connection. This may be a wireless channel (eg Wi-Fi connection), wired connection (eg DSL, cable modem, etc.), or a combination of both, suitable for accessing encoded video data stored on a file server. It may also include. The transmission of encoded video data from the storage device may be a streaming transmission, a download transmission, or a combination thereof.

The techniques described in this disclosure include over-the-air television broadcasts, cable television transmissions, satellite television transmissions, internet streaming video transmissions such as dynamic adaptive streaming over HTTP (DASH), and data storage. It may be applied to video coding with the support of any of a variety of multimedia applications, such as digital video encoded on a medium, decoding of digital video stored on a data storage medium, or other applications. In some examples, system 10 may be configured to support one-way or two-way video transmission to support applications such as video streaming, video playback, video broadcasting, and / or video telephony.

Computer readable medium 16 may be transitory media such as a wireless broadcast or wired network transmission, or storage such as a hard disk, flash drive, compact disk, digital video disk, Blu-ray disk, or other computer readable media. Media may be included (ie, non-transitory storage media). In some examples, a network server (not shown) may receive encoded video data from source device 12 and provide the encoded video data to destination device 14 via, for example, a network transmission. Similarly, a computing device in a media generation facility, such as a disc stamping facility, may receive encoded video data from source device 12 and generate a disc that includes the encoded video data. Thus, computer readable medium 16 may be understood to include one or more computer readable media of various forms, in various examples.

Input interface 26 of destination device 14 receives information from computer readable medium 16. The information of computer readable medium 16 may include syntax information defined by video encoder 22 of video encoder 22 and also used by video decoder 30, which syntax information may include blocks. And syntax elements that describe the characteristics and / or processing of other coded units, eg, groups of pictures (GOPs). Storage media 28 may store encoded video data received by input interface 26. Display device 32 displays decoded video data to a user and displays various display devices, such as cathode ray tubes (CRT), liquid crystal displays (LCD), plasma displays, organic light emitting diode (OLED) displays, or other types of display devices. It may also include any of these.

Each of video encoder 22 and video decoder 30 is one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic May be implemented as any of a variety of suitable video encoder and / or video decoder circuitry such as software, hardware, firmware or any combination thereof. If the techniques are implemented in part in software, the device may store the instructions for the software in a suitable non-transitory computer readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Each of video encoder 22 and video decoder 30 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined CODEC for a separate device.

In some examples, video encoder 22 and video decoder 30 may operate according to a video coding standard. Example video coding standards include ITU-T H.261, ISO / IEC MPEG-1 Visual, ITU-T H.262 or ISO / IEC MPEG-2 Visual, ITU-T H.263, ISO / IEC MPEG-4 Visual and ITU-T H.264 (also known as ISO / IEC MPEG-4 AVC), including but not limited to its scalable video coding (SVC) and multi-view video coding (MVC) extensions) . In addition, new video coding standards, namely high efficiency video coding (HEVC) or ITU-T H.265 (its range and screen content coding extensions, 3D video coding (3D-HEVC) and multiview extensions (MV- HEVC) and Scalable Extensions (SHVC)) by the Joint Collaboration Team on Video Coding (JCT-VC) of the ITU-T Video Coding Expert Group (VCEG) and the ISO / IEC Motion Picture Expert Group (MPEG). Developed. Video coding standards also include proprietary video codecs such as Google VP8, VP9, VP10, and video codecs developed by other organizations, such as the Alliance for Open Media.

In some examples, video encoder 22 and video decoder 30 may be configured to operate in accordance with other video coding techniques and / or standards, including new video coding techniques searched by Joint Video Exploration Team (JVET). It may be. JVET performs testing according to a software model called Joint Exploratory Model (JEM).

As will be described in more detail below, in one example of the present disclosure, video decoder 30 receives a block of video data, determines an intra prediction mode for the block of video data, and determines the determined intra prediction mode. May be configured to determine whether to use the PDPC mode to decode a block of video data based at least on. Similarly, video encoder 22 receives a block of video data, determines an intra prediction mode for encoding a block of video data, and encodes the PDPC to encode a block of video data based at least on the determined intra prediction mode. It may be configured to determine whether to use the mode.

In HEVC and other video coding specifications, a video sequence typically includes a series of pictures. Pictures may also be referred to as “frames”. The picture may include three sample arrays labeled S _L , S _Cb , and S _Cr . S _L is a two-dimensional array (eg, a block) of luma samples. S _Cb is a two-dimensional array of Cb chrominance samples. S _Cr is a two-dimensional array of Cr chrominance samples. Chrominance samples may also be referred to herein as "chroma" samples. In other instances, the picture may be monochrome and may only contain an array of luma samples.

To generate an encoded representation of a picture (eg, an encoded video bitstream), video encoder 22 may generate a set of coding tree units (CTUs). Each of the CTUs may include a coding tree block of luma samples, two corresponding coding tree blocks of chroma samples, and syntax structures used to code the samples of the coding tree blocks. In monochrome pictures or pictures with three separate color planes, the CTU may include syntax structures used to code samples of a single coding tree block and a coding tree block. The coding tree block may be an N × N block of samples. CTU may also be referred to as a “tree block” or “maximum coding unit (LCU)”. The CTUs of HEVC may be largely similar to macroblocks of other standards such as H.264 / AVC. However, a CTU is not necessarily limited to a particular size and may include one or more coding units (CUs). A slice may include integer CTUs sequentially ordered in raster scan order.

To generate a coded CTU, video encoder 22 recursively performs quadtree partitioning on the coding tree blocks of the CTU to convert the coding tree blocks into coding blocks, thus referred to as "coding tree units". You can also divide. The coding block is an N × N block of samples. A CU may include a coding block of luma samples and two corresponding coding blocks of chroma samples of a picture having a luma sample array, a Cb sample array, and a Cr sample array, and syntax structures used to code the samples of the coding blocks. It may be. In monochrome pictures or pictures with three separate color planes, a CU may include a single coding block and syntax structures used to code the samples of the coding block.

Video encoder 22 may partition a coding block of a CU into one or more prediction blocks. The prediction block is a rectangular (ie square or non-square) block of samples to which the same prediction is applied. The prediction unit (PU) of the CU may include a prediction block of luma samples, two corresponding prediction blocks of chroma samples, and syntax structures used to predict the prediction blocks. In monochrome pictures or pictures with three separate color planes, a PU may include syntax structures used to predict a single prediction block and a prediction block. Video encoder 22 performs prediction blocks (eg, luma, Cb, and Cr prediction blocks) for the prediction blocks (eg, luma, Cb, and Cr prediction blocks) of each PU of the CU. You can also create

Video encoder 22 may use intra prediction or inter prediction to generate predictive blocks for a PU. If video encoder 22 uses intra prediction to generate the predictive blocks of the PU, video encoder 22 may generate the predictive blocks of the PU based on decoded samples of the picture that includes the PU.

After video encoder 22 generates prediction blocks (eg, luma, Cb, and Cr prediction blocks) for one or more PUs of a CU, video encoder 22 generates one or more residual blocks for the CU. You can also create them. As one example, video encoder 22 may generate a luma residual block for a CU. Each sample in a luma residual block of a CU indicates a difference between a luma sample in one of the predictive luma blocks of the CU and a corresponding sample in the original luma coding block of the CU. In addition, video encoder 22 may generate a Cb residual block for the CU. In one example of chroma prediction, each sample in the Cb residual block of the CU may indicate a difference between the Cb sample in one of the predictive Cb blocks of the CU and the corresponding sample in the original Cb coding block of the CU. have. Video encoder 22 may also generate a Cr residual block for the CU. Each sample in the Cr residual block of the CU may indicate a difference between the Cr sample in one of the CU's predictive Cr blocks and the corresponding sample in the original Cr coding block of the CU. However, it should be understood that other techniques for chroma prediction may be used.

Moreover, video encoder 22 converts the residual blocks (eg, luma, Cb, and Cr residual blocks) of the CU into one or more transform blocks (eg, luma, Cb, and Cr transform blocks). You can also use quadtree partitioning to decompose. A transform block is a rectangular (eg, square or non-square) block of samples to which the same transform is applied. A transform unit (TU) of a CU may include a transform block of luma samples, two corresponding transform blocks of chroma samples, and syntax structures used to transform transform block samples. Thus, each TU of a CU may have a luma transform block, a Cb transform block, and a Cr transform block. The luma transform block of the TU may be a sub-block of the luma residual block of the CU. The Cb transform block may be a sub-block of the Cb residual block of the CU. The Cr transform block may be a sub-block of the Cr residual block of the CU. In monochrome pictures or pictures with three separate color planes, the TU may include syntax structures used to transform a single transform block and samples of the transform block.

Video encoder 22 may apply one or more transforms to a transform block of the TU to generate a coefficient block for the TU. For example, video encoder 22 may apply one or more transforms to a luma transform block of the TU to generate a luma coefficient block for the TU. The coefficient block may be a two-dimensional array of transform coefficients. The transform coefficients may be scalar quantities. Video encoder 22 may apply one or more transforms to the Cb transform block of the TU to generate a Cb coefficient block for the TU. Video encoder 22 may apply one or more transforms to the Cr transform block of the TU to generate a Cr coefficient block for the TU.

After generating a coefficient block (eg, a luma coefficient block, a Cb coefficient block, or a Cr coefficient block), video encoder 22 may quantize the coefficient block. Quantization generally refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent the transform coefficients to provide further compression. After video encoder 22 quantizes a coefficient block, video encoder 22 may entropy encode syntax elements that indicate quantized transform coefficients. For example, video encoder 22 may perform context-adaptive binary arithmetic coding (CABAC) on syntax elements indicative of quantized transform coefficients.

Video encoder 22 may output a bitstream that includes a sequence of bits that form a representation of coded pictures and associated data. Thus, the bitstream contains an encoded representation of the video data. The bitstream may include a sequence of network abstraction layer (NAL) units. The NAL unit includes an indication of the type of data in the NAL unit, and bytes containing the data in the form of a raw byte sequence payload (RBSP) interspersed with emulation prevention bits as needed. It is a syntax structure. Each of the NAL units may include a NAL unit header and encapsulates the RBSP. The NAL unit header may include a syntax element indicating the NAL unit type code. The NAL unit type code specified by the NAL unit header of the NAL unit indicates the type of the NAL unit. The RBSP may be a syntax structure that includes integer bytes encapsulated within a NAL unit. In some instances, the RBSP includes zero bits.

Video decoder 30 may receive the encoded video bitstream generated by video encoder 22. In addition, video decoder 30 may parse the bitstream to obtain syntax elements from the bitstream. Video decoder 30 may reconstruct pictures of video data based at least in part on syntax elements obtained from the bitstream. The process for reconstructing video data may generally be contrary to the process performed by video encoder 22. For example, video decoder 30 may use the motion vectors of the PUs to determine predictive blocks for the PUs of the current CU. In addition, video decoder 30 may inverse quantize coefficient blocks of TUs of the current CU. Video decoder 30 may perform inverse transforms on the coefficient blocks to reconstruct transform blocks of TUs of the current CU. Video decoder 30 may reconstruct coding blocks of the current CU by adding samples of predictive blocks for PUs of the current CU to corresponding samples of transform blocks of TUs of the current CU. By reconstructing the coding blocks for each CU of a picture, video decoder 30 may reconstruct the picture.

The quadtree plus binary tree (QTBT) partition structure is currently being studied by the Joint Video Exploration Team (JVET). In J. An et al, "Block partitioning structure for next generation video coding", International Telecommunications Union, COM16-C966, September 2015 ("VCEG proposed COM16-C966"), QTBT partitioning techniques are the The video coding standard has been described. Simulations show that the proposed QTBT structure may be more efficient than the quadtree structure used in HEVC.

In the QTBT structure described in the VCEG proposal COM16-C966, CTB is first partitioned using quadtree partitioning techniques, where quadtree splitting of one node occurs when the node reaches the minimum allowed quadtree leaf node size. Can be repeated. The minimum allowed quadtree leaf node size may be indicated to video decoder 30 by the value of syntax element MinQTSize. If the quadtree leaf node size is not greater than the maximum allowed binary tree root node size (eg, indicated by syntax element MaxBTSize), the quadtree leaf node may be further partitioned using binary tree partitioning. Binary tree partitioning of one node means that the node has a minimum allowed binary tree leaf node size (e.g., as indicated by the syntax element MinBTSize) or a maximum allowed binary tree (e.g., as indicated by the syntax element MaxBTDepth). It can be repeated until the depth is reached. VCEG proposal COM16-C966 uses the term “CU” to refer to binary-tree leaf nodes. In the VCEG proposal COM16-C966, CUs are used for transform and prediction (eg intra prediction, inter prediction, etc.) without any additional partitioning. In general, according to QTBT techniques, there are two splitting types for binary tree splitting: symmetrical horizontal splitting and symmetrical vertical splitting. In each case, the block is split by dividing the middle of the block horizontally or vertically. This is different from quadtree partitioning, which divides a block into four blocks.

In one example of a QTBT partitioning structure, the CTU size is set as 128 × 128 (eg, 128 × 128 luma block and two corresponding 64 × 64 chroma blocks), MinQTSize is set as 16 × 16, MaxBTSize is set to 64x64, MinBTSize (for both width and height) is set to 4, and MaxBTDepth is set to 4. Quadtree partitioning is first applied to the CTU to create quadtree leaf nodes. Quadtree leaf nodes may have a size from 16 × 16 (ie MinQTSize is 16 × 16) to 128 × 128 (ie, CTU size). According to one example of QTBT partitioning, if the leaf quadtree node is 128 × 128, the leaf quadtree node is added by the binary tree because the size of the leaf quadtree node exceeds MaxBTSize (ie 64 × 64). Cannot be split into Otherwise, the leaf quadtree node is further partitioned by the binary tree. Thus, the quadtree leaf node is also the root node for the binary tree and has a binary tree depth as zero. A binary tree depth reaching MaxBTDepth (eg 4) means no further splitting. A binary tree node with the same width as MinBTSize (eg 4) means no more horizontal splitting. Similarly, a binary tree node whose height is equal to MinBTSize means there is no more vertical splitting. Leaf nodes (CUs) of the binary tree are further processed (eg, by performing a prediction process and a transformation process) without any further partitioning.

2A illustrates an example of block 50 (eg, CTB) partitioned using QTBT partitioning techniques. As shown in FIG. 2A, using QTBT partitioning techniques, each of the resulting blocks is symmetrically split through the center of each block. FIG. 2B illustrates a tree structure corresponding to the block partitioning of FIG. 2A. Solid lines in FIG. 2B indicate quadtree splitting and dotted lines indicate binary tree splitting. In one example, at each splitting (ie non-leaf) node of the binary tree, the type of splitting (eg, horizontal or vertical) on which the syntax element (eg, flag) is performed is performed. Signaled to indicate, where 0 indicates horizontal splitting and 1 indicates vertical splitting. For quadtree splitting, there is no need to indicate the splitting type, because quadtree splitting always splits a block horizontally and vertically into four sub-blocks of the same size. .

As shown in FIG. 2B, at node 70, block 50 is split into four blocks 51, 52, 53, and 54, shown in FIG. 2A, using quadtree partitioning. Will be added. Block 54 is no longer split, and thus is a leaf node. At node 72, block 51 is further split into two blocks using binary tree partitioning. As shown in FIG. 2B, node 72 is marked 1, indicating vertical splitting. As such, splitting at node 72 results in a block that includes block 57 and both blocks 55 and 56. Blocks 55 and 56 are created by additional vertical splitting at node 74. At node 76, block 52 is further split into two blocks 58 and 59 using binary tree partitioning. As shown in FIG. 2B, node 76 is marked 1, indicating horizontal splitting.

At node 78, block 53 is split into four equally sized blocks using quadtree partitioning. Blocks 63 and 66 are generated from this quadtree partitioning and are not split further. At node 80, the upper left block is first split using vertical binary tree splitting to result in block 60 and the right vertical block. The right vertical block is then split into blocks 61 and 62 using horizontal binary tree splitting. The lower right block generated from quadtree splitting at node 78 is split into blocks 64 and 65 using horizontal binary tree splitting at node 84.

In one example of QTBT partitioning, luma and chroma partitioning may be performed independently of one another on I-slices, for example, as opposed to HEVC where quadtree partitioning is performed jointly on luma and chroma blocks. . That is, in some examples, luma blocks and chroma blocks may be partitioned separately so that the luma blocks and chroma blocks do not directly overlap. As such, in some examples of QTBT partitioning, the chroma blocks may be partitioned in such a way that at least one partitioned chroma block is not spatially aligned with a single partitioned luma block. That is, luma samples collocated with a particular chroma block may be in two or more different luma partitions.

In HEVC and JEM, an intra reference (eg, reference pixels / neighbor samples used for intra prediction) can be smoothed. In some examples, video encoder 22 and video decoder 30 may be configured to apply a filter to intra reference samples. In HEVC, mode dependent intra smoothing (MDIS) is an intra reference (eg, neighbor sample) before video encoder 22 and video decoder 30 generate intra prediction from neighbor samples for particular intra prediction modes. Are applied to the filter.

3 is a conceptual diagram illustrating an example of 35 intra prediction modes defined in HEVC. In HEVC, a luma block may be predicted using one of 35 intra predictions, including planar mode, DC mode, and 33 angular modes. The 35 modes of intra prediction defined in HEVC are indexed as shown in Table 1 below:

Video encoder 22 and video decoder 30 are intra-segment MDIS enabled based on how close or how dust the current intra prediction mode is to the horizontal or vertical direction (e.g., horizontal or vertical intra prediction direction). It may be configured to derive the prediction modes. In one example, video encoder 22 and video decoder 30 are specified based on an absolute difference between the intra mode index for the current intra prediction mode and the intra prediction mode index of the horizontal and / or vertical mode intra prediction mode. The intra mode may be configured to induce how close or how dusty the horizontal or vertical direction is. If this absolute difference exceeds a predetermined threshold (eg, the threshold may be block size dependent), video encoder 22 and video decoder 30 may be configured to apply an MDIS filter to reference samples. have. If this absolute difference is below a certain threshold (eg, the threshold may be block size dependent), video encoder 22 and video decoder 30 may be configured to not apply an MDIS filter to the reference samples. have. Examples of thresholds are 10 (eg for 4 × 4 blocks), 7 (eg for 8 × 8 blocks), 1 (eg for 16 × 16 blocks), and 0 (eg For example, 32 × 32 blocks). In other words, for intra prediction modes remote from the horizontal or vertical directions, video encoder 22 and video decoder 30 may not apply an intra reference filter. In some examples, video encoder 22 and video decoder 30 may not apply an MDIS filter for non-angle intra prediction modes such as DC mode or planar mode.

In JEM, MDIS has been replaced with a smoothing filter (eg, Reference Sample Adaptive Filtering (RSAF) or Adaptive Reference Sample Smoothing (ARSS)), which can be applied for all intra modes. The application of such smoothing filter to intra reference samples may be referred to as intra smoothing. In some examples, the smoothing filter is not applied for DC mode. Video encoder 22 may be configured to generate and signal a flag to indicate whether a smoothing filter is applied in the current block. Video decoder 30 may be configured to receive and parse this flag to determine whether to apply a smoothing filter to the current block.

In some examples, video encoder 22 may be configured not to signal such a flag as an explicit flag, but rather, video encoder 22 may indicate that a smoothing filter is a characteristic of transform coefficients (eg, parity of transform coefficients). It may also be configured to hide an indication of whether it applies in. Similarly, video decoder 30 may be configured to determine whether a smoothing filter is applied (eg, determine the value of a flag) from the nature of the transform coefficients (eg, the parity of the transform coefficients). For example, if the transform coefficients meet a predetermined parity condition (eg, odd or even), the value of the flag is derived as 1, otherwise the value of the flag is derived as 0.

Another tool used in JEM is position dependent intra prediction combination (PDPC) mode. The PDPC mode is a tool for weighting intra predictors and intra reference samples, where video encoder 22 and video decoder 30 are based on the block size and intra prediction mode of the block being coded (including width and height). To derive the weights.

The techniques described in this disclosure may be used in any combination and in any combination with other methods. Intra smoothing and PDPC modes are used for purposes of illustration and description, and the techniques of this disclosure are not limited to the examples and the disclosed methods may be applied to other tools.

The following sections describe techniques for determining parameters for position dependent intra prediction combination (PDPC) coding mode. Intra smoothing techniques of the present disclosure may be used with the PDPC mode. However, intra smoothing and PDPC modes are used for purposes of illustration and description, and the techniques of this disclosure are not limited to the examples and the disclosed methods may be applied to other tools.

When coding video data using the PDPC coding mode, video encoder 22 and / or video decoder 30 combine the predictions based on filtered and unfiltered reference values and based on the position of the predicted pixel. One or more parameterized equations may be used to define how to do this. The disclosure discloses that video encoder 22 tests sets of parameters (eg, using, for example, rate-distortion analysis) and optimizes parameters (eg, using video decoder 30). , Parameters that result in the best rate-distortion performance among those parameters being tested). In some examples, video decoder 30 may be configured to determine PDPC parameters from characteristics of the video data (eg, block size, block height, block width, etc.).

4A illustrates prediction (p) of a 4x4 block using an unfiltered reference (r) in accordance with the techniques of this disclosure. 4B illustrates prediction (q) of a 4x4 block using filtered reference (s) in accordance with the techniques of this disclosure. Although both FIGS. 4A and 4B illustrate a 4 × 4 pixel block and 17 (4 × 4 + 1) individual reference values, the techniques of this disclosure may be applied to any block size and number of reference values.

When performing the PDPC coding mode, video encoder 22 and / or video decoder 30 may utilize a combination between the filtered prediction (q) and the unfiltered prediction (p), thus, for the current block to be coded. The predicted block can be calculated using pixel values from both filtered reference (s) and unfiltered reference (r) arrays.

및

가 주어지면,

로 표기된, 픽셀의 조합된 예측된 값은 다음으로 정의되고,In one example of the techniques of PDPC, any two sets of pixel predictions, calculated using only unfiltered and filtered references r and s , respectively

And

Is given,

The combined predicted value of a pixel, denoted by, is defined as

는 조합 파라미터들의 세트이다. 가중치

의 값은 0 과 1 사이의 값일 수도 있다. 가중치들

와

의 합은 1 과 동일할 수도 있다.here

Is a set of combination parameters. weight

The value of may be a value between 0 and 1. Weights

Wow

The sum of may be equal to one.

는 훨씬 더 작은 파라미터들의 세트, 플러스 이들 파라미터들로부터 모든 조합 값들을 계산하기 위한 방정식으로 정의될 수도 있다. 이러한 예에서, 다음의 공식이 사용될 수도 있다:In certain examples, it may not be practical to have a set of parameters as large as the number of pixels in the block. In these examples,

May be defined as a much smaller set of parameters, plus an equation for calculating all combination values from these parameters. In this example, the following formula may be used:

및

는 예측 파라미터들이고, N 은 블록 사이즈이고,

및

는 각각 필터링되지 않은 및 필터링된 레퍼런스들을 사용하여, 특정 모드에 대해, HEVC 표준에 따르는 것을 사용하여 계산된 예측 값들이고, 그리고 here,

And

Is the prediction parameters, N is the block size,

And

Are predictive values computed using the conforming to the HEVC standard for a particular mode, using unfiltered and filtered references, respectively, and

및

에 할당된 전체 가중치들이 1 을 증가시키게 하는) 정규화 팩터이다.Is defined by the prediction parameters, i.e.

And

The total weights assigned to are increased by 1).

Equation 2 may be generalized for any video coding standard in Equation 2A:

및

는 예측 파라미터들이고, N 은 블록 사이즈이고,

및

는 각각 필터링되지 않은 및 필터링된 레퍼런스들을 사용하여, 특정 모드에 대해, 비디오 코딩 표준 (또는 비디오 코딩 스킴 또는 알고리즘) 에 따르는 것을 사용하여 계산된 예측 값들이고, 그리고here,

And

Is the prediction parameters, N is the block size,

And

Are predictive values computed using the compliant with video coding standard (or video coding scheme or algorithm), for a particular mode, using unfiltered and filtered references, respectively, and

및

에 할당된 전체 가중치들이 1 을 증가시키게 하는) 정규화 팩터이다.Is defined by the prediction parameters, i.e.

And

The total weights assigned to are increased by 1).

및

의 각각에 대한 값들 (즉, 각각의 예측 모드에 대한

및

의 35 개의 값들) 로 구성될 수도 있다. 이러한 값들은 비디오와 비트스트림으로 인코딩될 수도 있거나 또는 미리 인코더 및 디코더에 의해 알려진 상수 값들일 수도 있고 파일 또는 비트스트림으로 송신될 필요가 없을 수도 있다.

및

에 대한 값들은 트레이닝 비디오들의 세트에 대해 최상의 압축을 제공하는 예측 파라미터들에 대한 값들을 발견하는 것에 의해 최적화 트레이닝 알고리즘에 의해 결정될 수도 있다.These prediction parameters may include weights to provide an optimal linear combination of the predicted terms depending on the type of prediction mode used (eg, DC, plane, and 33 directional modes of HEVC). For example, HEVC includes 35 prediction modes. The lookup table includes prediction parameters for each of the prediction modes.

And

Values for each of (i.e., for each prediction mode

And

35 values). These values may be encoded in the video and the bitstream or may be constant values known by the encoder and decoder in advance and may not need to be transmitted in the file or bitstream.

And

The values for may be determined by the optimization training algorithm by finding values for prediction parameters that provide the best compression for the set of training videos.

및

에 대한 값들은 비디오 인코더 (22) 에 의해 즉시 생성되고 인코딩된 파일 또는 비트스트림으로 비디오 디코더 (30) 에 송신될 수도 있다.In another example, there are a plurality of predefined prediction parameter sets for each prediction mode (eg, in a lookup table) and the selected prediction parameter set (but not the parameters themselves) is an encoded file or bitstream. Is sent to the decoder. In another example,

And

The values for may be immediately generated by video encoder 22 and transmitted to video decoder 30 in an encoded file or bitstream.

In another example, instead of using HEVC prediction, a video coding device performing these techniques may use a modified version of HEVC, such as using 65 directional predictions instead of 33 directional predictions. Indeed, any type of intra-frame prediction may be used.

In another example, the formula can be selected to facilitate the calculations. For example, you can use the following types of predictors:

here

And

This approach may utilize the linearity of HEVC (or other) prediction. If h is defined as the impulse response of filter k from a predefined set,

(Where "*" represents convolution),

That is, the linearly combined prediction may be calculated from the linearly combined reference.

Formulas 4, 6, and 8 may be generalized for any video coding standard in Formulas 4A, 6A, and 8A:

here

And

This approach may utilize the linearity of prediction of the coding standard. If h is defined as the impulse response of filter k from a predefined set,

(Where "*" represents convolution),

That is, the linearly combined prediction may be calculated from the linearly combined reference.

(또한 p(x,y,r) 로서 기입됨) 은 필터링된 및 필터링되지 않은 레퍼런스들에 적용된,

(또한 p(x,y,s) 로서 기입됨) 와 동일하다. 추가적으로, 픽셀 예측들 p 및 q 는 등가일 수도 있다 (예를 들어, 동일한 입력이 주어지면 동일한 출력을 생성한다). 이러한 예에서, 공식들 (1) 내지 (8) 은 픽셀 예측

를 픽셀 예측

로 대체하여 재기입될 수도 있다.In an example, prediction functions may only use a reference vector (eg, r and s ) as input. In this example, the behavior of the reference vector does not change if the reference is filtered or unfiltered. If r and s are equal (e.g. some unfiltered reference r becomes equal to other filtered reference s ), then prediction functions, e.g.

(Also written as p (x, y, r )) is applied to the filtered and unfiltered references,

(Also written as p (x, y, s )). Additionally, pixel predictions p and q may be equivalent (eg, produce the same output given the same input). In this example, formulas (1) through (8) are pixel prediction

Pixel prediction

It can also be rewritten in place of.

및

). 이 경우에, r 과 s 가 동일하더라도,

및

는 동일하지 않을 수도 있다. 다시 말해서, 동일한 입력은, 그 입력이 필터링되었는지 여부에 의존하여 상이한 출력을 생성할 수 있다. 이러한 예에서,

는

로 대체될 수 없을 수도 있다.In another example, the prediction (eg, sets of functions) may be changed depending on the information for which the reference was filtered. In this example, different sets of functions may be written (eg,

And

). In this case, even though r and s are equal,

And

May not be the same. In other words, the same input can produce a different output depending on whether the input is filtered. In this example,

Is

May not be replaced.

The advantage of the prediction equations shown is that, with a parameterized formula, the sets of optimal parameters can be determined for different types of video textures using techniques such as training (ie, parameters that optimize prediction accuracy). ) Will be. This approach may, in turn, be extended in some examples by calculating several sets of prediction parameters and having an compression scheme where the encoder tests predictors from each set, for some conventional types of textures, The output is encoded as side information.

As discussed above, in some examples, video encoder 22 may determine the use of a particular video coding tool for one or more blocks of video data (eg, whether an intra smoothing filter and / or PDPC mode is applied). It may be configured to signal a flag or index to indicate. For example, video encoder 22 is configured to generate and signal a flag with a value of zero to indicate that a particular coding tool (eg, intra smoothing filter and / or PDPC mode) is not applied for the block. While a flag with a value of 1 may indicate that a coding tool (eg, an intra smoothing filter and / or PDPC mode) is applied for the block. Video decoder 30 may be configured to receive and parse this flag to determine whether to use a particular video coding tool for one or more blocks of video data associated with the flag.

In some examples, signaling a flag for a particular video coding tool may take a significant number of bits so that the compression efficiency obtained from using the video coding tool may be significantly reduced. This disclosure includes signaling for transform processing, including syntax elements for indicating video coding tool overhead signaling (eg, video coding tool usage and / or video coding tool parameters) along with signaling for other video coding processes. We describe the techniques for coupling

For example, video encoder 22 may be configured to generate and signal syntax elements for transform processing, including primary or secondary transform flags or indexes. The primary transform flag or index (eg, a multi-bit syntax element) may indicate a particular transform, among the multiple transforms, to use as the primary transform when coding a block of video data. Similarly, a secondary transform flag or index (eg, a multi-bit syntax element) may indicate, among the multiple transforms, a particular transform to use as the secondary transform when coding a block of video data. As one example, the primary transform may be a discrete cosine transform (DCT) or discrete sign transform (DST) based transforms, an enhanced multiple transform (EMT) used in JEM, or any other separable or non- It may be a separable transform. Example secondary transforms may include rotational transforms (ROT) or non-separable secondary transforms (NSST), both of which are currently employed in JEM. However, the secondary transform may include any other separable or non-separable transform. Primary and / or secondary transforms may include several sets of transforms, which may be indicated by index. For example, the transform set to use for any particular block of video data may depend on the intra prediction mode and / or intra prediction mode direction. That is, video encoder 22 and video decoder 30 determine the set of transforms available for a particular block of video data based on the intra prediction mode and / or intra prediction mode direction used to code the block of video data. It may be configured to.

In one example of this disclosure, video encoder 22 and / or video decoder 30 are one or more coding tools (eg, an intra reference sample) when a predetermined transform flag or index value (s) is signaled. Smoothing filter and / or PDPC mode) is applied for the block, and if a certain transform flag or index value (s) is not signaled, a predefined pre-defined rule indicating that no coding tool is applied It may be configured to follow these. In this case, any explicit flag to indicate the use of the video coding tool does not need to be signaled. Instead, the determination of whether a particular coding tool is used may be derived from transform signaling. The above examples include intra reference sample smoothing filters and PDPC mode, but other video coding tool usage may be coupled with transform signaling.

In one example, the video coding tool indicated by transform signaling may be an intra reference sample smoothing filter such as MDIS, ARSS, or any other smoothing and / or filtering applied to intra reference samples. In another example, the video coding tool indicated by transform signaling may be filtering applied to intra prediction, eg, PDPC mode, multi-parameter intra prediction (MPI) mode, or any other filtering applied for derived intra prediction. have.

For example, several tools may be used in combination, such as PDPC, MDIS and ARSS or just PDPC and MDIS. In one example, video encoder 22 and video decoder 30 are video coding specific for a block of video data coded with a predetermined secondary transform (eg, as indicated by the secondary transform index or indexes). It may also be configured to apply the tool. For example, video decoder 30 may be configured to determine whether to use a particular coding tool (eg, MDIS, ARSS, etc.) based on the value of an index indicating a certain type of secondary transform. In this way, the use of the secondary transform and at least one other coding tool may be represented by a single syntax element.

In one example, video decoder 30 may decide to use the PDPC mode only when certain secondary transforms are applied, as indicated by the secondary transform (NSST) indexes. Similarly, video encoder 22 may decide to use the PDPC mode only when certain secondary transforms are applied. For example, video encoder 22 and video decoder 30 may be configured to use the PDPC mode when a particular secondary transform is used (eg, when the value NSST index is equal to 1). In another example, video encoder 22 and video decoder 30 set the PDPC mode for certain intra prediction modes regardless of the secondary transform used (eg, as indicated by the value of the secondary transform index). It may be configured to use. For example, video encoder 22 and video decoder 30 may be configured to apply PDPC mode in cases where intra prediction mode is planar mode, and / or DC mode, or any other modes.

In another example, video encoder 22 and video decoder 30 are MDIS video coding tool (or other intra only for certain secondary transforms (eg, as indicated by the value of the secondary transform (NSST) index). Reference sample smoothing filters). As one example, video encoder 22 and video decoder 30 may be configured to apply the MDIS video coding tool (or other intra reference sample smoothing filters) only for an NSST index equal to three.

In some examples, if the use of more than one video coding tool depends on the transform used for the block (eg, the video coding tool is mapped to a transform index), the mapping of the video coding tool to the transform will be mutually exclusive. It may be. That is, in one example, each video coding tool corresponds to a different transform index.

The above examples can be combined. For example, video encoder 22 and video decoder 30 may be configured to apply PDPC mode for an NSST index of 1, and video encoder 22 and video decoder 30 may be configured for an NSST index of 3. It may be configured to apply an MDIS or other intra reference smoothing filter. In addition, the use of video encoder 22 and video decoder 30 may be configured to always apply a PDPC mode to a block of video data coded using the planar intra prediction mode regardless of the NSST index for the block. .

In another example, video encoder 22 and video decoder 30 may be configured to apply an ARSS video coding tool when the NSST index is equal to two.

If the utilization of different coding tools (eg PDPC, NSST, EMT, ARSS, MDIS, MPI, ROT) has multiple options, instead of signaling separate indices for each of the coding tool, video encoder 22 May be configured to signal only one unified index. In this example, the value of the unified index specifies how the different coding tools are coupled. In one example, if PDPC mode is designed with three different sets of parameters and NSST is designed with three different sets of NSST cores, instead of signaling PDPC indexes and NSST indexes separately, video encoder 22 ) May signal only one unified index, but this unified index value specifies the utilization of both PDPC mode and NSST. For example, when this unified index is equal to 0, neither PDPC nor NSST apply. When this unified index is equal to 1, PDPC mode parameter set 1 and NSST core 1 are used. When this unified index is equal to 2, PDPC mode parameter set 2 and NSST core 2 are used. When this unified index is equal to 3, PDPC mode parameter set 3 and NSST core 3 are used. That is, different PDPC modes are bundled with different NSST indexes. In another example, for different NSST indices, an MDIS filter with different filter coefficients may be applied.

Coupling between one tool (eg PDPC, ARSS, and / or MDIS) and a transform (eg EMT, NSST) includes intra prediction mode, block width and height, block partitioning depth, transform coefficients However, the present invention may rely on already coded information, which is not limited thereto. For example, for different intra prediction modes, PDPC mode may be coupled with different NSST indices. For example, for intra prediction mode 0, PDPC mode is coupled with NSST index 1, and for intra prediction mode 1, PDPC is coupled with NSST index 2.

The next section is about strong intra reference filtering. In U.S. Provisional Application No. 62 / 445,207, filed January 11, 2017, and U.S. Patent Application No. 15 / 866,287, filed January 9, 2018, a strong division free intra smoothing method is described. do. In some examples, if non-of-power-2 division is used, video encoder 22 and video decoder 30 may be configured to split the process into several parts. Where video encoder 22 and video decoder 30 may be configured to perform only two power-of-2 divisions for each portion of the process. This technique may be implemented as a simple bit shift operation. In this disclosure, more detailed examples are described. Consider a rectangular block, where in JEM, a division of powers of non-2 is used due to the division by (width + height) of the block. 5 shows an example where the filtering process is divided into several parts, for the non-square block 200.

As shown in FIG. 5, the filtering process includes left intra reference samples 202 and top intra reference samples 204 (indicated by black boxes), as well as right bottom intra reference samples 206 and top right. Intra reference samples 208 (indicated by dotted boxes) are performed. The division used is a power of non-2. Video encoder 22 and video decoder 30 may be configured to split the filtering process into portions for the horizontal and vertical directions, such that one portion corresponds to the width and / or height of block 200. The other part becomes the remaining length. In this particular example, the remainder is the width length for vertical filtering and the height length for horizontal filtering (ie, lower left intra reference samples 206 and right upper intra reference samples 208 in a dotted box). to be. As can be seen, since each portion may be required to be a size whose width and height are powers of two, the filtering process can be performed with power of two.

In addition, depending on the filtering process, some samples may be copied. For example, if the filtering formula is (length-i) * a + i * b, then i is from 1 to length-1. The length is the size of the sample array to be filtered. The length can be, for example, width + height. The values a and b may be the last samples of the sample array to be filtered.

It can be seen that one sample is not filtered for i = 0 and this sample can be copied directly. When the filtering process is split into several parts, the number of directly copied samples may increase. This may prevent additional samples from being filtered in each direction, and these samples may be copied directly. Direct copy may mean that no filtering process is applied for those samples.

Which samples may be copied directly may be variable. In one example of this disclosure, video encoder 22 and video decoder 30 transfer the directly copied sample (s) to the end of the intra reference samples in each direction, i.e., for the lower left samples and the horizontal for vertical filtering. In the case of filtering, it may be configured to put in the upper right samples. In this way, the samples may be used less often in intra prediction. The accuracy of these samples is less sensitive to the efficiency of intra prediction because these samples are the furthest from the block.

In another example, the directly copied samples can be placed in each part of the filtering process. In the example above, it may be one example in each of the black and dotted areas of filtering. That is, video encoder 22 and video decoder 30 are each of left reference samples 204, lower left reference samples 206, upper reference samples 202, and right upper reference samples 208, respectively. One directly copied sample may be placed in the. In one example, directly copied samples may be placed at the end of each portion. For example, video encoder 22 and video decoder 30 may position the directly copied sample below the left reference samples 204. Similarly, video encoder 22 and video decoder 30 may position the directly copied sample below the left lower reference samples 206. In addition, video encoder 22 and video decoder 30 may position the directly copied sample at the right end of the upper reference samples 202. Video encoder 22 and video decoder 30 may also position the directly copied sample at the right end of the right upper reference samples 208. The advantage of this design is the uniformity of the filtering process since there is no need to group directly copied samples in a given area.

In another example, the directly copied samples can be placed in the upper left region 201 (eg, the beginning of the block boxes of the samples 204 and 202). In a more general example, directly copied samples may be placed in any location within intra reference samples.

In another example, video encoder 22 and video decoder 30 are fixed N-tap linear filters instead of two-tap bilinear filters so that splitting operations using non- power divisors of two can be avoided. Strong smoothing can also be achieved. In one example, a 5-tap or 7-tap Gaussian filter is used to replace the 2-tap bilinear strong smoothing filter, where the parameters of the Gaussian filter are pre-defined or include block size, block shape, intra prediction mode. However, the present invention may rely on already coded information, which is not limited thereto.

In one example of this disclosure, video encoder 22 and video decoder 30 use intra prediction to code a non-square block, and intra, along two portions, one along the height or width of the block. It may be configured to apply strong intra reference filtering to the intra reference samples in the first portion associated with the reference samples, and the second portion associated with the remaining intra reference samples.

Video encoder 22 and video decoder 30 may be further configured to copy at least one reference sample directly from the first portion. In another example, video encoder 22 and video decoder 30 may be further configured to copy at least one reference sample directly from the second portion. In another example, video encoder 22 and video decoder 30 may be further configured to copy at least one reference sample directly from both the first portion and the second portion.

6 is a block diagram illustrating an example video encoder 22 that may implement the techniques of this disclosure. 6 is provided for illustrative purposes and should not be considered limiting of the techniques as broadly exemplified and described in this disclosure. The techniques of this disclosure may be applicable to various coding standards or methods. Video encoder 22 may be configured to perform the combined coding tool and transform signaling techniques described above. In addition, video encoder 22 may be configured to perform strong intra reference filtering as described above.

In the example of FIG. 6, video encoder 22 includes prediction processing unit 100, video data memory 101, residual generation unit 102, transform processing unit 104, quantization unit 106, inverse quantization unit ( 108, inverse transform processing unit 110, reconstruction unit 112, filter unit 114, decoded picture buffer 116, and entropy encoding unit 118. Prediction processing unit 100 includes inter prediction processing unit 120 and intra prediction processing unit 126. Inter prediction processing unit 120 may include a motion estimation unit and a motion compensation unit (not shown).

Video data memory 101 may be configured to store video data to be encoded by the components of video encoder 22. Video data stored in video data memory 101 may be obtained from video source 18, for example. Decoded picture buffer 116 may be a reference picture memory that stores reference video data for use in encoding video data by video encoder 22, eg, in intra or inter coding modes. . Video data memory 101 and decoded picture buffer 116 may include dynamic random access memory (DRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices, including synchronous DRAM (SDRAM). It may be formed by any of a variety of memory devices, such as. Video data memory 101 and decoded picture buffer 116 may be provided by the same memory device or separate memory devices. In various examples, video data memory 101 may be on-chip with other components of video encoder 22 or off-chip with respect to those components. Video data memory 101 may be the same as or part of storage media 20 of FIG. 1.

Video encoder 22 receives video data. Video encoder 22 may encode each CTU in a slice of a picture of the video data. Each of the CTUs may be associated with equally sized luma coding tree blocks (CTBs) and corresponding CTBs of a picture. As part of encoding the CTU, prediction processing unit 100 may perform partitioning to gradually divide the CTBs of the CTU into smaller blocks. In some examples, video encoder 22 may partition blocks using a QTBT structure. Smaller blocks may be coding blocks of CUs. For example, prediction processing unit 100 may partition the CTB associated with the CTU according to the tree structure. According to one or more techniques of this disclosure, for each individual non-leaf node of the tree structure at each depth level of the tree structure, there are a plurality of allowed splitting patterns for the individual non-leaf node. The video block corresponding to the individual non-leaf node is partitioned into video blocks corresponding to the child nodes of the individual non-leaf node according to one of the plurality of allowable splitting patterns.

Video encoder 22 may encode the CUs of the CTU to generate encoded representations of the CUs (ie, coded CUs). As part of encoding a CU, prediction processing unit 100 may partition coding blocks associated with the CU among one or more PUs of the CU. Thus, each PU may be associated with a luma prediction block and corresponding chroma prediction blocks. Video encoder 22 and video decoder 30 may support PUs having various sizes. As indicated above, the size of a CU may refer to the size of the luma coding block of the CU, and the size of the PU may refer to the size of the luma prediction block of the PU. Assuming that the size of a particular CU is 2N × 2N, video encoder 22 and video decoder 30 are PU sizes of 2N × 2N or N × N for intra prediction, and 2N × 2N, 2N for inter prediction. It may support symmetric PU sizes of × N, N × 2N, N × N, or the like. Video encoder 22 and video decoder 30 may also support asymmetric partitioning for PU sizes of 2N × nU, 2N × nD, nL × 2N, and nR × 2N for inter prediction.

Inter prediction processing unit 120 may generate predictive data for a PU by performing inter prediction on each PU of a CU. The predictive data for the PU may include predictive blocks of the PU and motion information for the PU. Inter prediction processing unit 120 may perform different operations on the PU of the CU depending on whether the PU is an I slice, a P slice, or a B slice. In an I slice, all PUs are intra predicted. For this reason, if the PU is in an I slice, inter prediction processing unit 120 does not perform inter prediction on the PU. Thus, for blocks encoded in I-mode, the predicted block is formed using spatial prediction from previously encoded neighboring blocks within the same frame. If the PU is in a P slice, inter prediction processing unit 120 may generate the predictive block of the PU using unidirectional inter prediction. If the PU is in a B slice, inter prediction processing unit 120 may generate the predictive block of the PU using unidirectional or bidirectional inter prediction.

Intra prediction processing unit 126 may generate prediction data for the PU by performing intra prediction on the PU. The predictive data for the PU may include the predictive blocks of the PU and various syntax elements. Intra prediction processing unit 126 may perform intra prediction on PUs in I slices, P slices, and B slices.

To perform intra prediction on a PU, intra prediction processing unit 126 may use multiple intra prediction modes to generate multiple sets of prediction data for the PU. Intra prediction processing unit 126 may generate a predictive block for a PU using samples from sample blocks of neighboring PUs. Neighboring PUs may be to the top, top and right, top and left, or left of the PU, assuming the left-right, up-down encoding order for PUs, CUs, and CTUs. . Intra prediction processing unit 126 may use various numbers of intra prediction modes, eg, 33 directional intra prediction modes. In some examples, the number of intra prediction modes may depend on the size of the region associated with the PU.

Prediction processing unit 100 predicts the PUs of the CU from the predictive data generated by inter prediction processing unit 120 for PUs or the predictive data generated by intra prediction processing unit 126 for PUs. You can also select data. In some examples, prediction processing unit 100 selects the prediction data for the PUs of the CU based on the rate / distortion metrics of the sets of prediction data. The predictive blocks of the selected prediction data may be referred to herein as the selected prediction blocks.

Residual generation unit 102 includes coding blocks (eg, luma, Cb and Cr coding blocks) for the CU and selected prediction blocks (eg, prediction luma, Cb and Cr) for the PUs of the CU. Based on the blocks), residual blocks (eg, luma, Cb, and Cr residual blocks) for the CU may be generated. For example, residual generation unit 102 may determine that each sample in the residual blocks is equal to the difference between the sample in the coding block of the CU and the corresponding sample in the corresponding selected prediction block of the PU of the CU. Residual blocks of a CU may be generated to have.

Transform processing unit 104 may perform quadtree partitioning to partition the residual blocks associated with a CU into transform blocks associated with TUs of the CU. Thus, a TU may be associated with a luma transform block and two chroma transform blocks. The sizes and positions of the luma and chroma transform blocks of the TUs of a CU may or may not be based on the sizes and positions of the predictive blocks of the PUs of the CU. A quadtree structure known as a "residual quadtree" (RQT) may include nodes associated with each of those regions. TUs of a CU may correspond to leaf nodes of an RQT.

Transform processing unit 104 may generate transform coefficient blocks for each TU of a CU by applying one or more transforms to the transform blocks of the TU. Transform processing unit 104 may apply various transforms to a transform block associated with a TU. For example, transform processing unit 104 may apply a discrete cosine transform (DCT), a directional transform, or a conceptually similar transform to the transform block. In some examples, transform processing unit 104 does not apply transforms to the transform block. In such examples, the transform block may be treated as a transform coefficient block.

Quantization unit 106 may quantize the transform coefficients in the coefficient block. The quantization process may reduce the bit depth associated with some or all of the transform coefficients. For example, the n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m. Quantization unit 106 may quantize a coefficient block associated with a TU of the CU based on a quantization parameter (QP) value associated with the CU. Video encoder 22 may adjust the quantization applied to coefficient blocks associated with a CU by adjusting the QP value associated with the CU. Quantization may introduce loss of information. Thus, quantized transform coefficients may have lower accuracy than the original ones.

Inverse quantization unit 108 and inverse transform processing unit 110 may apply inverse quantization and inverse transforms to the coefficient block, respectively, to reconstruct the residual block from the coefficient block. Reconstruction unit 112 may add the reconstructed residual block to corresponding samples from one or more prediction blocks generated by prediction processing unit 100 to generate a reconstructed transform block associated with the TU. By reconstructing the transform blocks for each TU of a CU in this manner, video encoder 22 may reconstruct the coding blocks of the CU.

Filter unit 114 may perform one or more deblocking operations to reduce blocking artifacts in coding blocks associated with the CU. Decoded picture buffer 116 may store the reconstructed coding blocks after filter unit 114 performs one or more deblocking operations on the reconstructed coding blocks. Inter prediction processing unit 120 may perform inter prediction on PUs of other pictures using a reference picture that includes the reconstructed coding blocks. In addition, intra prediction processing unit 126 may use intra reconstructed coding blocks in decoded picture buffer 116 to perform intra prediction on other PUs in the same picture as the CU.

Entropy encoding unit 118 may receive data from other functional components of video encoder 22. For example, entropy encoding unit 118 may receive coefficient blocks from quantization unit 106 and receive syntax elements from prediction processing unit 100. Entropy encoding unit 118 may perform one or more entropy encoding operations on the data to generate entropy encoded data. For example, entropy encoding unit 118 may include a CABAC operation, a context adaptive variable length coding (CAVLC) operation, a variable-to-variable length coding operation, a syntax based context adaptive binary arithmetic coding (SBAC) operation, Probability interval partitioning entropy (PIPE) coding operations, exponential-Golomb encoding operations, or other types of entropy encoding operations may be performed on the data. Video encoder 22 may output a bitstream that includes entropy encoded data generated by entropy encoding unit 118. For example, the bitstream may include data indicating the RQT for the CU.

7 is a block diagram illustrating an example video decoder 30 that is configured to implement the techniques of this disclosure. 7 is provided for purposes of explanation and is not limiting on techniques, as broadly exemplified and described in this disclosure. For purposes of explanation, this disclosure describes video decoder 30 in the context of HEVC coding. However, the techniques of this disclosure may be applicable to other coding standards or methods, including JVET. Video decoder 30 may be configured to receive and parse signaled syntax elements in accordance with the combined coding tool and transform signaling techniques described above. In addition, video decoder 30 may be configured to perform strong intra reference filtering as described above.

In the example of FIG. 7, video decoder 30 includes entropy decoding unit 150, video data memory 151, prediction processing unit 152, inverse quantization unit 154, inverse transform processing unit 156, reconstruction unit 158, filter unit 160, and decoded picture buffer 162. Prediction processing unit 152 includes motion compensation unit 164 and intra prediction processing unit 166. In other examples, video decoder 30 may include more, fewer, or different functional components.

Video data memory 151 may store encoded video data, such as an encoded video bitstream, to be decoded by the components of video decoder 30. Video data stored in video data memory 151 may be, for example, from computer readable medium 16, for example from a local video source such as a camera, via wired or wireless network communication of video data, or physically. By accessing data storage media. Video data memory 151 may form a coded picture buffer (CPB) that stores encoded video data from an encoded video bitstream. Decoded picture buffer 162 stores reference video data for output or for use in decoding video data by video decoder 30, for example in intra- or inter-coding modes. It may be a reference picture memory. Video data memory 151 and decoded picture buffer 162 may include dynamic random access memory (DRAM) including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. It may be formed by any of a variety of memory devices, such as. Video data memory 151 and decoded picture buffer 162 may be provided by the same memory device or separate memory devices. In various examples, video data memory 151 may be on-chip with other components of video decoder 30 or off-chip with respect to those components. Video data memory 151 may be the same as or part of storage media 28 of FIG. 1.

Video data memory 151 receives and stores encoded video data (eg, NAL units) of the bitstream. Entropy decoding unit 150 may receive encoded video data (eg, NAL units) from video data memory 151 and parse the NAL units to obtain syntax elements. Entropy decoding unit 150 may entropy decode entropy encoded syntax elements in NAL units. Prediction processing unit 152, inverse quantization unit 154, inverse transform processing unit 156, reconstruction unit 158, and filter unit 160 are decoded video data based on syntax elements extracted from the bitstream. You can also create Entropy decoding unit 150 may generally perform a process that is contrary to the process of entropy encoding unit 118.

According to some examples of this disclosure, entropy decoding unit 150 may determine the tree structure as part of obtaining syntax elements from the bitstream. The tree structure may specify how an initial video block, such as a CTB, is partitioned into smaller video blocks, such as coding units. According to one or more techniques of this disclosure, for each individual non-leaf node of the tree structure at each depth level of the tree structure, there are a plurality of allowed splitting patterns for the individual non-leaf node. The video block corresponding to the individual non-leaf node is partitioned into video blocks corresponding to the child nodes of the individual non-leaf node according to one of the plurality of allowable splitting patterns.

In addition to obtaining syntax elements from the bitstream, video decoder 30 may perform a reconstruction operation on an unpartitioned CU. To perform a reconstruction operation on a CU, video decoder 30 may perform a reconstruction operation on each TU of the CU. By performing a reconstruction operation for each TU of a CU, video decoder 30 may reconstruct the residual blocks of the CU.

As part of performing a reconstruction operation on a TU of a CU, inverse quantization unit 154 may inverse quantize, ie, dequantize, coefficient blocks associated with the TU. After inverse quantization unit 154 inverse quantizes the coefficient block, inverse transform processing unit 156 may apply one or more inverse transforms to the coefficient block to generate a residual block associated with the TU. For example, inverse transform processing unit 156 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotation transform, an inverse directional transform, or other inverse transform to the coefficient block.

If a PU is encoded using intra prediction, intra prediction processing unit 166 may perform intra prediction to generate predictive blocks of the PU. Intra prediction processing unit 166 may use intra prediction mode to generate predictive blocks of the PU based on samples of spatially neighboring blocks. Intra prediction processing unit 166 may determine an intra prediction mode for the PU based on one or more syntax elements obtained from the bitstream.

If a PU is encoded using inter prediction, entropy decoding unit 150 may determine motion information for the PU. Motion compensation unit 164 may determine one or more reference blocks based on the motion information of the PU. Motion compensation unit 164 may generate predictive blocks (eg, predictive luma, Cb and Cr blocks) for the PU based on one or more reference blocks.

Reconstruction unit 158 includes transform blocks (eg, luma, Cb and Cr transform blocks) for the TUs of the CU and predictive blocks (eg, luma, Cb and Cr blocks) of PUs of the CU. In other words, if applicable, intra prediction data or inter prediction data may be used to reconstruct coding blocks (eg, luma, Cb and Cr coding blocks) for a CU. For example, the reconstruction unit 158 may take samples of transform blocks (eg, luma, Cb, and Cr transform blocks) from corresponding blocks of predictive blocks (eg, luma, Cb, and Cr prediction blocks). In addition to the samples, the coding blocks of the CU (eg, luma, Cb and Cr coding blocks) may be reconstructed.

Filter unit 160 may perform a deblocking operation to reduce blocking artifacts associated with coding blocks of the CU. Video decoder 30 may store the coding blocks of the CU in decoded picture buffer 162. Decoded picture buffer 162 may provide reference pictures for subsequent motion compensation, intra prediction, and presentation on a display device, such as display device 32 of FIG. 1. For example, video decoder 30 may perform intra prediction or inter prediction operations on PUs of other CUs based on blocks in decoded picture buffer 162.

8 is a flowchart illustrating an encoding method of an example of the present disclosure. One or more structural components of video encoder 22 may be configured to perform the techniques of FIG. 8.

In the example of FIG. 8, video encoder 22 receives a block of video data 800, determines an intra prediction mode for encoding a block of video data 802, and based at least on the determined intra prediction mode. To determine 804 whether to use the PDPC mode to encode a block of video data. In one example, to determine whether to use PDPC, video encoder 22 may be further configured to determine to use the PDPC mode to encode a block of video data when the intra prediction mode is planar mode. It may be.

9 is a flowchart illustrating a decoding method of an example of the present disclosure. One or more structural components of video decoder 30 may be configured to perform the techniques of FIG. 9. In the example of FIG. 9, video decoder 30 receives a block of video data (900), determines an intra prediction mode for the block of video data (902), and at least based on the determined intra prediction mode. It may be configured to determine 904 whether to use the PDPC mode to decode a block of data.

In one example, video decoder 30 may be configured to determine to use the PDPC mode to decode a block of video data when the intra prediction mode is planar mode.

In another example, video decoder 30 receives a syntax element associated with a primary transform or a secondary transform used for a block of video data, and determines the use of one or more video coding tools based on the value of the syntax element. As one or more video coding tools determine the use of the one or more video coding tools, which are video coding techniques other than a primary or secondary transform, and apply one or more coding tools to a block of video data based on the determined use. It may be configured to.

In another example, video decoder 30 may use the PDPC to decode a block of video data based on the determined intra prediction mode and the value of a syntax element associated with the primary transform or secondary transform used for the block of video data. It may be configured to determine whether.

In another example, video decoder 30 decodes a block of video data when the intra prediction mode is planar mode regardless of the value of the syntax element associated with the primary or secondary transform used for the block of video data. May be configured to decide to use the PDPC mode. In one example, the primary transform is one of DCT, DST, or EMT. In another example, the secondary transform is either a rotation transform or an NSST. In another example, one or more video coding tools include one or more of PDPC mode, MDIS, RSAF, ARSS, or MPI.

In another example, video decoder 30 decodes a block of video data using the PDPC mode and the determined intra prediction mode when it is determined to use the PDPC mode, or when it is not determined to use the PDPC mode. It may be configured to decode a block of video data using the intra prediction mode determined without using the PDPC mode. Video decoder 30 may be further configured to output a decoded block of video data.

Certain aspects of the present disclosure have been described with respect to the HEVC standard and extensions of JEM for purposes of illustration. However, the techniques described in this disclosure may be useful for other video coding processes, including other standard or proprietary video coding processes that are under development or not yet developed.

A video coder may refer to a video encoder or video decoder, as described in this disclosure. Similarly, a video coding unit may refer to a video encoder or video decoder. Similarly, video coding may refer to video encoding or video decoding, where applicable.

Depending on the example, certain acts or events of any of the techniques described herein may be performed in a different sequence and may be added, merged, or removed in their entirety (eg, all described acts Or events are not essential for the implementation of the techniques). Moreover, in certain examples, acts or events may be performed concurrently, eg, through multi-threaded processing, interrupt processing, or multiple processors, rather than sequential.

In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer readable media may be computer readable storage media corresponding to a tangible medium such as data storage media, or to facilitate transfer of a computer program from one place to another, for example, in accordance with a communication protocol. It may include communication media including any medium. In this manner, computer readable media may generally correspond to (1) non-transitory tangible computer readable storage media or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and / or data structures for implementing the techniques described in this disclosure. . The computer program product may include a computer readable medium.

By way of example, and not limitation, such computer readable storage media may be in the form of RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or instructions or data structures. And any other medium that can be used to store desired program code and can be accessed by a computer. Also, any connection is properly termed a computer readable medium. For example, if commands are sent from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, wireless, and microwave, Cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are included in the definition of the medium. However, it should be understood that computer readable storage media and data storage media do not comprise connections, carrier waves, signals, or other temporary media, but instead are directed to non-transitory, tangible storage media. Disks and disks, as used herein, include compact disks (CD), laser disks, optical disks, digital versatile disks (DVD), floppy disks, and Blu-ray disks, where: Discs usually reproduce data magnetically, while discs optically reproduce data with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The instructions may be one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integration. Or by separate logic circuits. As such, the term “processor” as used herein may refer to any of the structures described above or any other structure suitable for the implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding or integrated into a combined codec. Also, the techniques can be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (eg, a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, the various units may be provided by a collection of interoperable hardware units, including one or more processors as described above, combined in a codec hardware unit or together with suitable software and / or firmware. It may be.

Various examples have been described. These and other examples are within the scope of the following claims.

Claims (30)

A method of decoding video data,
Receiving a block of video data;
Determining an intra prediction mode for the block of video data; And
Determining whether to use a position-dependent prediction combination (PDPC) mode to decode the block of video data based at least on the determined intra prediction mode. . The method of claim 1,
Determining whether to use the PDPC,
Determining to use the PDPC mode to decode the block of video data when the intra prediction mode is planar mode. The method of claim 1,
Receiving a syntax element associated with a primary transform or a secondary transform used for the block of video data;
Determining usage of one or more video coding tools based on a value of the syntax element, wherein the one or more video coding tools are video coding techniques other than the primary or secondary transform. Determining use of the tools; And
Applying the one or more coding tools to the block of video data based on the determined use. The method of claim 3, wherein
The one or more video coding tools include the PDPC mode, and the method of decoding the video data,
Whether to use the PDPC to decode the block of video data based on the determined intra prediction mode and the value of the syntax element associated with the primary transform or the secondary transform used for the block of video data. And determining the video data. The method of claim 4, wherein
Determining whether to use the PDPC,
The PDPC mode to decode the block of video data when the intra prediction mode is planar regardless of the value of the syntax element associated with the primary or secondary transform used for the block of video data. Determining to use the method. The method of claim 3, wherein
Wherein the primary transform is one of a discrete cosine transform (DCT), a discrete sine transform (DSP), or an enhanced multiple transform (EMT). The method of claim 3, wherein
Wherein the secondary transform is one of a rotation transform or a non-separable secondary transform (NSST). The method of claim 3, wherein
The one or more video coding tools perform one or more of the PDPC mode, mode dependent intra smoothing (MDIS), reference sample adaptive filtering (RSAF), adaptive reference sample smoothing (ARSS), or multi-parameter intra prediction (MPI). And decoding the video data. The method of claim 3, wherein
And wherein the syntax element is an index to the primary transform or the secondary transform. The method of claim 3, wherein
And wherein the syntax element is an index into a set of transforms. The method of claim 1,
Decoding the block of video data using the PDPC mode and the determined intra prediction mode when it is determined to use the PDPC mode; or
Decoding the block of video data using the intra prediction mode determined without using the PDPC mode if it is not determined to use the PDPC mode. The method of claim 11,
Outputting the decoded block of video data. An apparatus configured to decode video data, the apparatus comprising:
A memory configured to store a block of video data; And
One or more processors in communication with the memory,
The one or more processors,
Receive the block of video data;
Determine an intra prediction mode for the block of video data; And
And determine whether to use a position dependent prediction combination (PDPC) mode to decode the block of video data based at least on the determined intra prediction mode. The method of claim 13,
In order to determine whether to use the PDPC, the one or more processors,
And further determine to use the PDPC mode to decode the block of video data when the intra prediction mode is a planar mode. The method of claim 13,
The one or more processors,
Receive a syntax element associated with a primary transform or a secondary transform used for the block of video data;
Determining the use of one or more video coding tools based on the value of the syntax element, wherein the one or more video coding tools are video coding techniques other than the primary transform or the secondary transform. Determine; And
And apply the one or more coding tools to the block of video data based on the determined use. The method of claim 15,
The one or more video coding tools include the PDPC mode, the one or more processors,
Whether to use the PDPC to decode the block of video data based on the determined intra prediction mode and the value of the syntax element associated with the primary transform or the secondary transform used for the block of video data. And further configured to determine the video data. The method of claim 16,
In order to determine whether to use the PDPC, the one or more processors,
The PDPC mode to decode the block of video data when the intra prediction mode is planar regardless of the value of the syntax element associated with the primary or secondary transform used for the block of video data. And further configured to determine to use the video data. The method of claim 15,
Wherein the primary transform is one of a discrete cosine transform (DCT), a discrete sine transform (DST), or an enhanced multiple transform (EMT). The method of claim 15,
And the secondary transform is one of a rotation transform or a non-separable secondary transform (NSST). The method of claim 15,
The one or more video coding tools perform one or more of the PDPC mode, mode dependent intra smoothing (MDIS), reference sample adaptive filtering (RSAF), adaptive reference sample smoothing (ARSS), or multi-parameter intra prediction (MPI). And an apparatus configured to decode the video data. The method of claim 15,
And the syntax element is an index for the primary transform or the secondary transform. The method of claim 15,
And the syntax element is an index to a set of transforms. The method of claim 13,
The one or more processors,
Decode the block of video data using the PDPC mode and the determined intra prediction mode when it is determined to use the PDPC mode; or
And decode the block of video data using the intra prediction mode determined without using the PDPC mode if it is not determined to use the PDPC mode. The method of claim 23, wherein
The one or more processors,
And further configured to output the decoded block of video data. An apparatus configured to decode video data, the apparatus comprising:
Means for receiving a block of video data;
Means for determining an intra prediction mode for the block of video data; And
Means for determining whether to use a position dependent prediction combination (PDPC) mode to decode the block of video data based at least on the determined intra prediction mode. A non-transitory computer readable storage medium storing instructions.
The instructions, when executed, cause one or more processors of the device configured to decode video data,
Receive a block of video data;
Determine an intra prediction mode for the block of video data; And
And determine whether to use a position dependent prediction combination (PDPC) mode to decode the block of video data based at least on the determined intra prediction mode. A method of encoding video data,
Receiving a block of video data;
Determining an intra prediction mode for encoding the block of video data; And
Determining whether to use a position dependent prediction combination (PDPC) mode to encode the block of video data based at least on the determined intra prediction mode. The method of claim 27,
Determining whether to use the PDPC,
Determining to use the PDPC mode to encode the block of video data when the intra prediction mode is planar mode. A device configured to encode video data,
A memory configured to store a block of video data; And
One or more processors in communication with the memory,
The one or more processors,
Receive the block of video data;
Determine an intra prediction mode for encoding the block of video data; And
And determine whether to use a position dependent prediction combination (PDPC) mode to encode the block of video data based at least on the determined intra prediction mode. The method of claim 29,
In order to determine whether to use the PDPC, the one or more processors,
And further determine to use the PDPC mode to encode the block of video data when the intra prediction mode is planar mode.

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